Recasting his role in setting a “red line” on Syria, President Barack Obama insisted on Wednesday that Congress and the world will lose credibility if Bashar Assad’s alleged chemical weapons massacre goes unpunished.

“My credibility’s not on the line. The international community’s credibility is on the line, and America and Congress’ credibility is on the line,” Obama said during a visit to Stockholm, Sweden.

“I do have to ask people, well, if, in fact, you’re outraged by the slaughter of innocent people, what are you doing about it?” Obama asked. “The moral thing to do is not to stand by and do nothing.”

The president rejected any notion that he needs to use military force against Syria in order to preserve his personal standing in the world after calling a chemical weapons attack a “red line” in an Aug. 20, 2012, press conference.

“I didn’t set a red line. The world set a red line,” he insisted. “The world set a red line when governments representing 98 percent of the world’s population said the use of chemical weapons are abhorrent and passed a treaty forbidding their use even when countries are engaged in war.”

And “Congress set a red line when it ratified that treaty. Congress set a red line when it indicated, in a piece of legislation titled the Syria Accountability Act, that some of the horrendous things that are happening on the ground there need to be answered for,” he added.

The Chemical Weapons Convention, which Syria never signed, does not call for unilateral military force in response to violations by countries not party to the treaty. The Syria Accountability Act imposes tough economic sanctions on Syria, but it does not envision unilateral military force. And Obama mentioned neither in his fateful remarks one year ago.

Still, Obama insisted on Wednesday, “that wasn’t something I just kind of made up. I didn’t pluck it out of thin air. There’s a reason for it.”

His arguments recalled then-President George W. Bush’s warnings in the runup to the invasion of Iraq that world credibility was on the line because of a series of U.N. Security Council resolutions warning Saddam Hussein about possessing weapons of mass destruction, and Bush’s insistence that Congress’ credibility was at stake because it passed the Iraq Liberation Act that made “regime change” official U.S. policy.

“I’m very mindful of the fact that around the world and here in Europe in particular, there are still memories of Iraq,” Obama said.

“Keep in mind, I’m somebody who opposed the war in Iraq and am not interested in repeating mistakes of us basing decisions on faulty intelligence,” he added. “We believe very strongly, with high confidence, that in fact chemical weapons were used and that Mr. Assad was the source.”

Obama’s comments came as the deeply divided Congress wrestled with whether to approve legislation granting him authorization to use force against Syria.

Asked what he would do if lawmakers rejected the measure, Obama bluntly told lawmakers that he does not need their permission to strike Syria. And he challenged Congress to do more than “sit on the sidelines (and) snipe.”

“As commander in chief, I always preserve the right and the responsibility to act on behalf of America’s national security. I do not believe that I was required to take this to Congress,” Obama said.

“But I did not take this to Congress just because it’s an empty exercise; I think it’s important to have Congress’s support on it,” Obama said at a press conference with Swedish Prime Minister Fredrik Reinfeldt.

The president expressed confidence that Congress will ultimately give him its green light for military action against the Syrian president’s forces, whom Washington accuses of massacring civilians with chemical weapons on Aug. 21.

“I believe Congress will approve it,” he said.

“We can send a very clear strong message in favor of the prohibition against using chemical weapons. We can change Assad’s calculus about using them again. We can degrade his capabilities so that he does not use them again,” Obama said.

“What I’m talking about is an action that is limited in time and in scope, targeted at the specific task of degrading his capabilities and deterring the use of those weapons again,” the president said.

And Obama said Congress must be more invested in the use of American military force abroad — at least when American national security, or that of an ally's, is not directly and imminently threatened.

“It’s important for us to get out of the habit of just saying, ‘well, we’ll let the president kind of stretch the boundaries of his authority as far as he can. Congress will sit on the sidelines, snipe. If it works, the sniping will be a little less. If it doesn’t, a little more.' But either way, the American people and their representatives are not fully invested in what are tough choices,” Obama said.